Liquid metal recorder

ABSTRACT

An uninterrupted stream or continuous liquid bridge of an electrically conductive ink is propelled under pressure against a carrier for marking thereon. Symbol formation is effected through the agency of magnetic deflection resulting from interaction of a pair of magnetic flux fields of relative variable intensities. A first of the flux fields is induced about the ink stream by passing a current through it as it travels across the span between the nozzle from which it has been ejected to the carrier; and the second field is disposed about the first. In a preferred embodiment, the ink is an electrical conductor, being a metal or metallic composition with a melting point, such that it will flow at printing temperature but will solidify as it contacts the carrier. By providing an impervious or imperforate endless carrier, for example, of metal fabrication a formed symbol may be removed therefrom to enable reuse of the carrier and metal salvage.

United States Patent [72] Inventor Johannes F. Gottwlld Park Ridge, Ill.[2|] Appl. No. 840,947 [22] Filed July 11, 1969 [45] Patented July 27,1971 [73] Assignee Teletype Corporation Skokie, Ill.

[54] LIQUID METAL RECORDER 3,298,030 1/1967 Lewis etal PrimaryExaminer-Joseph W. l-lartary Attorneys-J. L. Landis and R. P. Millerrelative variable intensities. A first of the flux fields is inducedabout the ink stream by passing a current through it as it travelsacross the span between the nozzle from which it has been ejected to thecarrier; and the second field is disposed about the first. In apreferred embodiment, the ink is an electrical conductor, being a metalor metallic composition with a melting point, such that it will flow atprinting temperature but will solidify as it contacts the carrier. Byproviding an impervious or imperforate endless carrier, for example, ofmetal fabrication a formed symbol may be removed therefrom to enablereuse of the carrier and metal salvage.

PATENTEUJULZTIQYI 3596285 to) 64% 24 58 38 I2 28 H6. 5 ZGJ (j INVENTORJOHANNES F. GOTTWALD ATTORNEY LIQUID METAL RECORDER BACKGROUND OF THEINVENTION The present invention relates to printing and the like with anink stream controlled by an electrical phenomenon and moved across aspan from a source onto a target surface of a carrier.

I-leretofore known processes of the indicated type, fall into twoclasses in most of which a printing stream comprises a succession ofdrops. In one class, formation of a symbol character or patterncomprising a display is effected by electrostatic stream deflection. Inthe other, stream deflection for character or pattern fonnation is byelectromagnetic means. The present invention is concerned only with thelatter class.

While the art of printing with a stream according to heretofore knownprocesses and using heretofore known means enables production ofhundreds of lines of acceptable characters per minute, control of thepath of individual drops in a succession by presently known technologyfalls shortof an optimum level. In consequence printing of characterswith fine or distinct outlines has not been uniformly obtainable.Moreover, sophisticated and expensive equipment is required for dropmanagement to obtain even present levels of character definitron.

The problems of stream control are minimized in a conventional processby spacing a drop supply source and a carrier apart only 5 shortdistance. In practice such distance does not generally exceed a quarterinch. Such spacing places a limit on the size of a display which cam bemade efiiciently using heretofore known processes of the indicated type.

It is an object of the present invention to print with a clear outlineby a process in which a stream of ink is electromagnetically controlledfor forming intelligence on a carrier.

It is another object of the invention to increase the size of charactersand the like which can be generated in an economically practical processof the indicated type over the maximum size available using heretoforeknown apparatus. Thereby, large displays of the type used, for example,for providing a continuous record of market transactions, such as areexhibited in a board room of a stockbroker's office, can be producedcontinuously.

But in terms of material requirements forsuch large and continuousdisplays, if consumed at theretofore known rates, but increased inproportion to increase in size, the high cost would severely limit anywidespread enjoyment of a process or apparatus satisfying the foregoingobjects.

It is therefore an additional object of the invention to minimize use tomaterials in a process of the indicated class.

It is a further object of the invention that materials employed in suchprocess be salvaged for reuse.

SUMMARY OF THE INVENTION To achieve the foregoing, and other objectswhich will become apparent from ensuing description, and in accordancewith the invention, in one aspect, an electrically conductive liquid inkin a bridge is caused to flow between a source and a carrier across aspan in a process for printing. The bridge is electromagneticallydeflected while the ink is flowing to form an intelligence symbol on thecarrier. To effect the'process, means are provided for completing anelectrically conductive circuit through the ink stream and between anozzle from which the ink is projected and the carrier.

According to another aspect of the invention, a combination for writingand the like comprises a carrier for displaying an intelligence patternand an arrangement for removing the pattern from the carrier. Anelectrically conductive marking stream has an end impinged on thecarrier. An induced magnetic field is disposed about the stream; andmeans are provided for electromagnetically changing the position ofstream impingement on said carrier for printing the pattern.

2 DESCRIPTION or THE DRAWINGS DETAILED DESCRIPTION OF THE INVENTIONReferring now more particularly to the drawings, printing apparatusgenerally designated 10 comprises a jet or stream forming head or nozzle12 and a carrier 14 spaced from said nozzle by a span 24. A surface 16defines the carrier. It is aligned with the nozzle for blocking the pathof a bridge or stream 18 of an ink from the nozzle to the end that itwill be marked with anintelligence symbol, character or patter 20 at aprinting station. In the preferred embodiment, the carrier is endlessand is arranged for continuous movement past the station, for example,in the direction of arrow 48.

As used herein the term printing" is not intended in a limited sense butincludes writing or other symbol, character or pattern formation with anink. The term ink as used in is intended to include not only dye orpigment-containing materials, but any flowable substance or compositionsuited for application to surface 16 for forming symbols, characters, orpatterns of intelligence by marking.

Means for supplying ink under pressure comprises a reservoir 22 in fluidcommunication with nozzle 12. The arrangement is such that ink will movefrom the nozzle 12 with sufficient force to impel it as across span 24in a continuous uninterrupted liquid stream for impingement on saidcarrier for printing.

Nozzle 12 as well as carrier 14 are electrical conductors. In theillustrated embodiment the carrier is of impervious steel fabrication,its surface 16 being a black oxide of the type formed by anodization.Ink for stream 18 also is a conductor and, while it is flowing in acourse or path across pan 24 for intelligence formation on carrier 16,it comprises an electrically conductive bridge in a circuit completed bymeans, herein shown as a conductor 26, and electrically connecting thenozzle and the carrier.

An alternating current generator 28 is shown arranged in series withconductor 26 and comprises means for providing an induced magnetic fieldabout stream 18. In the illustrated embodiment, a magnet 30 is arrangedfor providing a magnetic flux or second field about the stream. Thesefields are coacting or interacting and comprise means for deflecting thebridge or stream of ink 18, the deflection being effected by couplingthe induced magnetic field with the second magnetic field and varyingtheir relative intensities.

To that end the magnet has a gap 32 arranged and proportioned forpassing the stream 18. Moreover, said magnet, as shown, is anelectromagnet comprised of E laminations or core member 36 and 1"laminations or core member 38, both of which may be conventional. A pairof series connected coils 34 are disposed about opposed legs 40 and 42of member 36. The coils are energized by means, such as a battery 44,for inducing a fixed polarity in the magnetizable material of the coremembers. The arrangement is such that a pair of magnetic flux paths willbe induced in said core members, polarized with north and south magneticpoles disposed, as shown in FIG. 1 by conventional designations N and8", on opposite sides of gap 32. The illustrated fixed polar arrangementmay be reversed with equanimity.

If desired, the illustrated magnet may be replaced by a permanent magnet(not shown). However, the electromagnetic current. On the other hand, ifthe intensity of the magnetic flux field of magnet 30 is fixed, therelative strengths of the interacting fields for effecting streamdeflection will be adjusted by adjusting the level of current output ofgenerator 28 in any well-known manner.

The preferred ink is characterized by viscosity and surface tensioncharacteristics such that liquid continuity will be maintained over span24 under the force with which it is moving in bridge or stream 18.Implicit in such requirement is that the pressure applied to the ink information of said stream is sufficient to form a jet and to impartenough energy to carry the jet as a continuous liquid mass to surface 16notwithstanding the deflective forces which are or may be applied. Furthermore, the color of the ink and the color of the carrier should besuch that good optical contrast is formed therebetween followingprinting.

The preferred ink is of a hot melt" type. That is to say, it will assumea solid phase at the temperature of carrier 14 and a liquid phase atsome higher temperature. For most anticipated practical situations themelting point of the ink likely will not be above a level which can betolerated normally by the human body; and the ink likely will be solidat room temperature, this being the temperature at which the carrier isexpected to be employed for most operations.

The range of commercially available ink compositions which could meetthe requirements of the invention are not known at the present time.However, satisfactory printing according to the invention has beenachieved with a conductive metal alloy as ink. It is extremely hard atroom temperature and adheres well to the surface of the carrier.Constituents, proportions, and melting points of the ink are set forthin the following chart:

A jet stream of ink can be formed from a nozzle having an insidediameter of 0.003 inch with sufficient force to travel, undeflected, andin liquid continuity a distance of 3 feet, by applying 60 pounds ofpressure per square inch to said alloy in a liquid phase in reservoir22. Effective printing has been achieved on a carrier of exemplaryfabrication and 1 inch wide over a span 24 of 7.8 inches from a nozzleof such dimension. DC current providing a flux density of 4,200 Gaussacross gap 32, of 0.04 inch is adequate to deflect stream 18 from suchnozzle with a generator 28 having a peak of three volts at 150 cyclesper second.

While the disclosed arrangement is adapted for marking a continuoustrace on surface 16, separated characters or symbols also can beproduced. To assist in such character formation masking meansexemplified by shield 56 can be mounted at or adjacent the stream pathat an intermediate position along span 24. To maintain requiredelectrical continuity, the shield is electrically connected to carrier14 by conductor means 58. By appropriate current control stream 18selectively then can be deflected onto shield 24 for effectivelyblocking stream fiowto the carrier.

For management of carrier 14, it may be entrained about a driven roller50 and a drive roller 52 which is spaced horizontally from the drivenroller. Character removing means may comprise a blade or scraper 54arranged in a fixed position spaced from the printing station such thatits inner end is disposed at or adjacent surface 16 for removing themetallic characters or pattern 20. The solid ink thus removedconveniently may be collected and reused by returning same to thereservoir which is adapted to be maintained at a temperaturesufficiently high to melt the material and assure it s retention in aliquid phase as it passes across span 24 during a print- HIE pl'OCflSS.

I claim:

1. in a system for recording discernible patterns:

a carrier formed in a closed loop of material of a first color;

means for advancing said color;

means for impelling a stream of marking material in a color contrastingwith said first color toward said carrier, said marking materialcharacterized by the ability to adhere to said carrier;

means for diverting said stream to form discernible pattern on saidcarrier; and

means positioned along the path of travel of said carrier for removingsaid pattern. 2. in a system according to claim 1, wherein said carrieris constructed of a first metal, and said stream of marking materialcomprises a molten second metal.

3. In a system for displaying intelligence patterns; a conductiverecording medium; means for directing a stream of electricallyconductive material of a color contrasting with the color of saidrecording medium toward said recording medium toward a point ofimpingement;

means for supplying a variable electric current indicative ofintelligence through said stream and said recording medium to induce avarying magnetic field about said stream,

means reacting with the induced magnetic field about said stream fordiverting said point of impingement of said stream on said recordingmedium to form intelligence patterns on said medium;

means for advancing said recording medium along a path relative to thepoint of impingement of said stream; and means cooperating with themoving recording medium for removing the intelligence pattern from saidmedium.

4. In a system according to claim 3 wherein said recording medium isconstructed of metal and said stream of electrically conductive materialcomprises molten metal.

5. An apparatus for generating a pattern of intelligence symbols whichcomprises:

a reservoir for receiving an electrically conducting liquid medium;

a nozzle connected to said reservoir in communication with said mediumin said reservoir;

means for projecting a liquid stream of said medium in electriccontinuity from said nozzle; an endless carrier of conductive andimpervious material mounted for movement in a cyclic path ininterceptive relation with said projected stream of conductive medium toreceive an impingement of said stream on said carrier at a point ofinterception of said stream with said cyclic path of said carrier and tocomplete a conductive path from said nozzle through said stream to saidcarrier;

means for passing an electric current from said nozzle,

through said stream to said carrier to establish a first magnetic fieldabout said stream;

means reacting with the first magnetic field for magnetically deflectingsaid stream of conductive medium to vary the position of said point ofinterception of said stream on said carrier and to generate a pattern ofintelligence symbols from said carrier; and

means mounted adjacent to said endless carrier for removing said patternof intelligence symbols from said carrier to render said carrier readyto again accept information at the point of impingement of said streamon said carrier.

6. An apparatus as defined in claim 5 wherein said removing meanscomprises a scraper for physically engaging and removing the patternfrom said carrier.

UNITED STATES PATENT OFFICE 569 CERTIFICATE OF CORRECTION Patent No.3,596,285 Dated y 971 Inventor(s) JOHANNES F. GQTTWALD It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 2, line 1, change "ensuring" to "ensuing-r.

Column t, line 9, change "color" to --carrier'-.

Column line 1 change "pattern" to -patterns--.

Signed and sealed this 8th day of August 1972.

(SEAL) Attest:

EDWARD M.FLE;T(?HER,JR. ROBERT GOT'I'SCHALK Attesting OfficerCommissioner of Patents

1. In a system for recording discernible patterns: a carrier formed in aclosed loop of material of a first color; means for advancing saidcolor; means for impelling a stream of marking material in a colorcontrasting with said first color toward said carrier, said markingmaterial characterized by the ability to adhere to said carrier; meansfor diverting said stream to form discernible pattern on said carrier;and means positioned along the path of travel of said carrier forremoving said pattern.
 2. In a system according to claim 1, wherein saidcarrier is constructed of a first metal, and said stream of markingmaterial comprises a molten second metal.
 3. In a system for displayingintelligence patterns; a conductive recording medium; means fordirecting a stream of electrically conductive material of a colorcontrasting with the color of said recording medium toward saidrecording medium toward a point of impingement; means for supplying avariable electric current indicative of intelligence through said streamand said recording medium to induce a varying magnetic field about saidstream, means reacting with the induced magnetic field about said streamfor diverting said point of impingement of said stream on said recordingmedium to form intelligence patterns on said medium; means for advancingsaid recording medium along a path relative to the point of impingementof said stream; and means cooperating with the moving recording mediumfor removing the intelligence pattern from said medium.
 4. In a systemaccording to claim 3 wherein said recording medium is constructed ofmetal and said stream of electrically conductive material comprisesmolten metal.
 5. An apparatus for generating a pattern of intelligencesymbols which comprises: a reservoir for receiving an electricallyconducting liquid medium; a nozzle connected to said reservoir incommunication with said medium in said reservoir; means for projecting aliquid stream of said medium in electric continuity from said nozzle; anendless carrier of conductive and impervious material mounted formovement in a cyclic path in interceptive relation with said projectedstream of conductive medium to receive an impingement of said stream onsaid carrier at a point of interception of said stream with said cyclicpath of said carrier and to complete a conductive path from said nozzlethrough said stream to said carrier; means for passing an electriccurrent from said nozzle, through said stream to said carrier toestablish a first magnetic field about said stream; means reacting withthe fIrst magnetic field for magnetically deflecting said stream ofconductive medium to vary the position of said point of interception ofsaid stream on said carrier and to generate a pattern of intelligencesymbols from said carrier; and means mounted adjacent to said endlesscarrier for removing said pattern of intelligence symbols from saidcarrier to render said carrier ready to again accept information at thepoint of impingement of said stream on said carrier.
 6. An apparatus asdefined in claim 5 wherein said removing means comprises a scraper forphysically engaging and removing the pattern from said carrier.